+#else /* not HAVE_VSNPRINTF */
+# if HAVE_VSPRINTF
+# warning "Using VSPRINTF. Buffer overflow could happen!"
+ vsprintf(buf_ptr, s, ap);
+ break;
+# else /* not HAVE_VPRINTF */
+# error "Your standard library has neither vsnprintf nor vsprintf defined. One of them is required!"
+# endif
+#endif